Zigzag sewing machine



.A. B. E. KARLSSON ZIG June 17, 1952 -ZAG SEWING MACHINE 2 SHEETS--SHEET 1 Filed Feb. 16, 1946 June 17, 1952 A. B. E. KARLssoN ZIG-zAG SEWING MACHINE Filed Feb. 16. 1946 2 SHEETS-SHEET 2 Ande/95. E.

BY 2617* @van INVENTOR /z/-Zs so 2z ATTORNEY` Patented June 17, 1952 Anders Bertil 'Emanuel Karlsson,

Sweden,

Huskvarna,

assigner to Husqvarna Vapenfabriks Aktiebolag, Huskvarna, Sweden, a corporation .of Sweden AppIicat'ionFebruary 16, 19.46, SerialNo. 648,183 In Sweden December 28, 1944 7 Claims.

The present invention refers to zig-zag sewing machines and has for its primary object to proyidefa suitable construction of elements, by means Vof which the amplitude of the Zig-zag movement may be varied. Another object is to provide means for adjusting the initial position of the oscillatory movement. For obtaining an accurate movement vit is necessary that the yvarious elements participating in the movement cooperate `with :plays as small as possible, and a further Object of the invention is to providea `compact construction with a comparatively small number of parts having small plays at the surfaces in contact vwith one another.

It is previously known to arrange the needle bar of the sewing machine in a frame or the like having an oscillatory movement imparted thereto at ri-ght angles to the "feeding direction of the work piece with the aid of a link -rod or the like, one end of which is adjustable on an Yoscillating member to a Igreater or smaller distance from the -oscillatory axis of this member, so that a variation -of the oscillation amplitude of Vthe needle and thus of the widthof' the zig-zag seam'can be obtained. The invention refers primarily to the construction and arrangement of this member and -of the parts cooperating therewith. The'substantial distinguishing feature -of'the invention vis that said member is arranged to be driven by an eccentric in engagement therewith. In .comparison with known means -said arrangement results, in the first place, in a simplified and vmore condensed construction operating on the needle bar frame with a few elements only.

Aiding toward the provision of va simple and Vexactly operating construction is also the feature that the link rod transmitting the oscillatory movement to the needle bar frame may be guided in the oscillating member through a cylindrical or approximately cylindrical-guide element,'-which may -be-read-ily finished to exact measures.

Furthermore, the arrangement maybe provided with a bar adapted for the adjustment of the bearing of the link rod in the guide element of the oscillating member, said bar being so disposed as to extend at right angles or approximately so tothe link rod, when the latter takes its middle position. This arrangement results, above all, in that the link rod is brought to the same ylevel in theV two extreme positions of the oscillating mem.- ber, whereby the movement is rendered symmetrical and oblique stitches are avoided.

lFurther fea-tures of the invention andl'advan- Atages inherent therein will appear from the following "description of a form' of embodiment illus- 2 .trated in the accompanyingv drawings. Fig. -l shows a vertical projection of the arrangement with an indicationof the outlines of the housing of the sewing lmach-ine. Fig. 2 is a vertical-cross section through the arm -of the housing ofthe Vmachine' on a plane lextending through the oscillating member, which is constructed in the vform of arguide-member. Fig-s. 3=`and4 show the guidemember per se in a vertical and a horizontal projection respectively. Figs. `5', I6 and 7 Yshow a mounting element for the linkin a vertical projection, a vertical elevation and 4a horizontal projection, respectively. 'F-ig. 8 shows a diagrammatic View of the arrangement intendedto elucidatethe general rmode of operation, and Fig. @is perspective View partly in section show-ing the details of Fig. 2.

As will appearfrom the drawings, an oscillatory frame l2 is'mounted on a pin I4 `in the upper portion of Vthe arm pertaining to the 'housing' lll ofthe sewing machine, said pin being so arranged that the frame may oscillate atright angles-t0 the feeding direction of the machine. vThis frame Aforms a guiding means forY the needle barv '18. which is adapted Ato `move up and down in `the Vframe I2 and may be driven for this purpose by any suitable Icontrivance known perv se (not shown). To provide the zig-zag movementl the 'frame l2 is pivota-lly connected` AbyA meansfof' a bolt I8 to the one end of a link rod 20, the'other end of which is pivotally mounted by means 'of a pin- 22 on a plunger-like slide piece ,24, which is adjustable into vdifferent "positions along oscillating guide-member26. The guide-'member 26 -is swingably mounted by 'means of .aligned pins 28 in an adjustable mounting or bearing member' 3Q extending transversely through the arm o'f the `frame While being `mounted withits one en'd pin 32 in the vrear wall 34 'of lsaid arm and with its other 'end' bearing A3S in 'a plate secured in the front wall 40 of the arm ofthe frame. YThe oscillatory movement of the guidemember `26 about the pins 28 `is effected, in a manner-to beV set forth hereinafter, bymeans of an eccentric 42 connected to a spiral .or .Worm gear44 on a shaft 46, which is carried in the Wall 34 by means of. bearing 48. :The spiral .Qr'woim gear Mis in mesh with and driven `by a Spiral' or wormV gear 59 secured Von the arm shaft .52 off'the sewing machine, which shaft is driven vin any suitable manner known per se, for instance by means of a belt transmission means .and a ypedal-- driven crank arrangement, an `electric motor or the like. The .bearing pins 28 Yfurthe'uitleg-111eIll.- ber 26"are eccentrically arranged relativelyto the axis of rotation of the mounting 36 (the centre line of the end pins 32. 36). so that the oscillatory axis of the guide member 26 changes position, if the mounting 38 is turned about the centre line of the end pins 32, 36. A handle 56 is non-rotatably connected, for instance by means of screws 54, to the end pin 36, through the actuation of which handle the mounting 3U may be turned through a certain angle. Arranged in the handle 56 is a ball 58 actuated by a spring 60 so as to be pressed into one or other of a number of recesses 62 in the plate 38, in order thus to determine a corresponding position for the handle and the mounting 3D.

The slide piece 24 forming a bearing for the link rod 28 has its lower end connected to a link 66 through a pin 64, said link 66 extending so that the link rod 28 is in its middle position approximately at right angles to said link. The link 56 is pivotally connected with its lower end to an arm'68, which is clamped to an adjusting shaft 18, which is mounted in the front wall 4i) and carries an adjusting arm l2 on the outer end thereof. By swinging the arm l2 into different positions, the link 66 may be caused to move the slide piece 24 upwardly or downwardly in the guide-member 26. The centre of the pin 22 may thus be adjusted between the lower position in iront o the centre line of the pins 28, about which the guide-member 26 oscillates, as shown by full lines in Fig. 1, and an upper position in front of the eccentric 42 (the link rod 20 is indicated here by a chain-dotted line in Fig. 1). In the lower position, the oscillatory movement of the guide-member 26 is not transmitted to the link rod 20, whereas in the upper position a displacement is imparted to the link rod by the guide-member, which displacement equals the double eccentricity of the eccentric 42. The first one of these positions consequently corresponds to a straight seam, while the latter position corresponds to a zig-zag seam of maximum Width (the maximum amplitude of the oscillatory movement of the needle bar frame). In intermediate positions of the slide piece 24, the zig-zag seam will obtain widths varying continuously between zero and a maximum value.

The eccentric 42 actuates the guide-member 26 directly, inasmuch as it is in engagement with a pair of projections 14 projecting from the rear side of the guide-member 26, between which projections the eccentric engages. The guidemember 26 thus carries the bearing part 24 for the link rod 2U of the needle bar frame while beingat the same time formed with engaging surfaces or the eccentric, which provides for a simplified, compact construction operating only with a few elements directly on the needle bar frame, so that the movement will be influenced by a minimum of bearing plays. Furthermore, the guide-member 26 is formed with a cylindrical guide surface 'I8 for the plunger-like slide piece 24, as will appear particularly from Figs. 3 and 4, whereby the sliding surfaces may be finished accurately at a relatively low cost, besides which it is possible in a simple manner to mount the link rod 28 with the end thereof centrally in relation to the guide, so that the play will not disturb the movement by an augmented amount. This central mounting is provided by the fact that the end of the link rod 20 projects into a transverse recess 80 (Fig. l) in the slide piece 24, and by the fact that the bearing pin 22 extends transversely through said recess, so that its geometrical axis or centre line intersects the axial line of the cylindrical sliding surfaces or takes a position in the proximity of said axial line. As will be seen from Figs. 3 and 4, the guide-member 26 has provided therein a lateral slot 82, through which the link rod 28 extends into the guide-member in the manner shown in Fig. 1. The longitudinally extending slot 82 permits a displacement of the link rod from the lower position shown in Fig. 1 into the upper position in front of the eccentric 42. When the link rod 26 takes a position right between these extreme positions, it extends, as stated, approximately at right angles to the link 66, whereby the link rod is brought to the same level in the two extreme positions of the oscillating guide-member 26, so that the movement becomes symmetrical.

The construction of the mounting 30 appears from Figs. 5-7. It is formed with two yokeshaped arcuate parts 84, 86, the part 84 extending in the mounted position, as shown in Fig. 2, downwardly underneath the arm shaft 52 of the machine, whereas the part 86 extends behind the bearing 36, so that space is provided for the guide-member 26 and the mounting thereof is rendered possible by means of the pins 28, for which apertures 88 are provided.

The mode of operation of the arrangement described will appear broadly from the diagrammatically represented Fig. 8. For the sake of clearness, the guide-member 26 is shown here with an exaggerated length, the mounting 3D being indicated as an arm, with which the guidemember 28 is connected by a pin 28. The link 30 may be adjusted by turning of the shaft 36 between two angular positions indicated by chaindotted lines AO and BO, respectively. In the middle position shown by full lines in the gure, the centre O of the shaft 36' and the centre of the pin 28 are located on the extension of the guiding means of the link. This position corresponds to an initial position of the needle bar I6 that may be designated as the middle initial position. If the link 38 be turned to the left into the position OA or to the right into the position OB, the needle bar frame will be displaced sideways by a corresponding distance, so that another left and right initial position respectively is obtained, that is to say, the whole oscillatory range of the needle is displaced with the amplitude thereof maintained, it being assumed here that the slide piece 24 takes an unaltered position in the guide-member 26. The amplitude of the zigzag movement may be varied by a displacement of the slide piece 24 along the guide-member, the amplitude being naught, when the slide piece 24 has the pin 22 in front of the centre of the pin 28' and the link rod 20 takes the position CD, While the amplitude has its maximum value, when the slide piece has been displaced up into a position in front of the eccentric 42, the link rod then taking the position CE. As will appear from the foregoing, displacement of the slide piece 24 along the link, that is to say the amplitude control, is effected by means of an adjusting contrivance, the operating member of which is represented in Fig. 2 by the arm 12. This adjusting contrivancemay be of any suitable kind with respect to the details thereof, and in particular it may be devised for instance as described in our patent application No. 10,581/44 with the title Means for the Adjustment of the Seam Width in Zigzag Sewing Machines.

The adjustment of the oscillatory range of the needle is effected by turning the handle 56 into diierent positions. It should be noted that this handle 56 is not influenced by the movement of the driven parts, but is stationary when the machine operates and may be adjusted without disadvantage, while the machine is in operation. The arrangement renders possible a continuous variation of the amplitude as well as of the position of the oscillatory range of the needle bar, so that widely varying Works may be performed with a machine fitted with this device.

What I claim is:

l. In a zig-zag sewing machine of the type having a needle bar frame adapted to apply oscillatory motion to the needle bar transversely of the feed direction of the work, means to vary the amplitude and initial position of the needle bar frame, comprising in combination with a rotary eccentric, an oscillatory member engaged by the eccentric to impart oscillations thereto and formed with a guide extending opposite to the eccentric, a connecting member displaceable along said guide for variation of the amplitude of the needle bar frame, a link connecting said connecting member with the needle bar frame, and an adjustable mounting or bell crank, the oscillatory member being pivoted to said bell crank for adjustment of the initial position or centre of oscillation thereof and thus of the needle bar frame.

2. In a zig-zag sewing machine of the type having a needle bar frame adapted to apply oscillatory motion to the needle bar transversely of the feed direction of the work, means to oscillate the frame and to vary the amplitude of oscillation. thereof comprising in combination with a pivoted oscillatory member and a rotary eccentric engaging said member for the operation thereof, a substantially cylindrical guide formed in said member, a slide piece displaceable in the longitudinal direction of said guide and connected with the needle bar frame, and means to set the slide piece at various positions in said guide.

3. In a zig-zag sewing machine of the type having a needle bar frame adapted to apply oscillatory motion to the needle bar transversely of the feed direction of the work, means to oscillate the frame and to vary the amplitude of oscillation thereof comprising in combination with a link connected with the needle bar frame, an oscillatory member provided with a guide, a slide piece slidably fitted to said guide and connected pivotally by the link to the needle bar frame, means to displace the slide piece along the guide, a rotary eccentric engaging the oscillatory member to impart oscillatory motion thereto, a mounting or bearing member for the oscillatory member Journailed to be turned through a certain angle about its axis, the oscillatory member being pivoted to said mounting the pivot being eccentric relatively to said aXis and parallel thereto, and means to turn the mounting to displace the pivot and thus the centre of oscillation of the needle bar frame.

4. In a sewing machine as claimed in claim 3 a housing having an overhanging arm, a rotary shaft located in said arm, means to transmit motion from the shaft to the eccentric, the mounting or bearing member comprising end pins eX- tending transversely of the arm shaft and journalled in opposite walls of the arm and further comprising yoke shaped arcuate parts one extending underneath the arm shaft and another extending laterally of the oscillatory member.

5. In a sewing machine as claimed in claim 3 a housing having an overhanging arm| a rotary shaft located in said arm, a worm gear transmission between said shaft and the eccentric to impart rotary motion to the latter, the eccentric being mounted on a shaft extending above the arm shaft transversely thereof.

6. In a sewing machine as claimed in claim 2 a link rod connecting the slide piece with the needle bar frame, said link rod being pivoted to the slide piece on an axis intersecting the axis of the cylindrical guide.

7. In a zig-zag sewing machine, a frame, a main drive shaft in said frame, an oscillatory needle bar supporting frame pivotally mounted on said Erst-mentioned frame, a rotary eccentric operatively connected to said drive shaft for rotation thereby, a link connected at one end thereof to the oscillatory frame, the other end of the link being pivotally connectedy to a slide member, a guide member operatively engaged with the eccentric and in which said slide member is disposed, and means engaged with said slide member for slidably adjusting same within said guide member.

ANDERS BERTIL MANUEL KARLSSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,331,099 Francis Feb. 17, 1920 FOREIGN PATENTS Number Country Date '7,213 Great Britain Dec. 16, 1909 

